Disclosed herein is an apparatus and method that senses photoreceptor failure in a xerographic printing apparatus.
Presently, image output devices, such as xerographic printers, xerographic multifunction media devices, xerographic machines, and other xerographic devices produce images on media sheets, such as paper, substrates, transparencies, plastic, cardboard, or other media sheets. To produce an image, a developing device applies marking material, such as toner, ink jet ink, or other marking material, to a latent image on a photoreceptor. A transfer device transfers the developed marking material to a media sheet or image transfer belt to provide a developed image for fusing or a second transfer step. A fuser assembly then affixes or fuses the developed image to the media sheet by applying heat and/or pressure to the media sheet.
Unfortunately, a photoreceptor is subject to scratching caused by a cleaning device used to clean residual marking material from the photoreceptor after the first transfer step. In electrostatic brush cleaning devices, micro-arcing between the brush fibers and the photoreceptor surface increases the photoreceptor surface roughness, Rz. In blade cleaning architectures, scratches can be generated from contamination from paper fiber, toner agglomerates, toner additives, etc. in the blade/photoreceptor nip. The halftone uniformity and hence image quality is a direct function of the surface roughness of the photoreceptor. As the surface roughness increases, white streaks in halftone areas appear on the customer output. Thus, image quality suffers as the scratching caused by micro-arcing or blade contamination increases the photoreceptor surface roughness. Overcoating the photoreceptor significantly improves the life of the photoreceptor. However, photoreceptors are still replaced before the end of their usable life in order to maintain 90% reliability with 90% confidence.
For example, a current life limiter of xerographic units is photoreceptor scratching from Paschen breakdown that occurs between the photoreceptor drum and electrostatic cleaner brush fibers. Service engineers replace the photoreceptor device at a specific interval, or sooner if close to the cycle alarm, even if the device is still performing acceptably. System run cost can be reduced by extending the life of the photoreceptor to its near failure point, instead of replacing it at a fixed interval. While use of overcoated photoreceptors extends the life of the device and lowers the run cost, significant reductions can be achieved through sensing of the impending photoreceptor device failure.
Thus, there is a need for an apparatus and method that senses impending photoreceptor failure in a xerographic printing apparatus.